Text classification may be relied on for various different computer applications. This classification may often use probabilistic techniques to analyze text and categorize it into one of two or more categories. Text classification is often used for various security measures, such as determining the authenticity of programs or documents. In another common form, it may be used to filter “spam” or unsolicited e-mail. Existing filters often rely on probabilistic text classification, basing their classification on the presence and frequency of particular words contained in an e-mail. While such filters can be effective, they can also be somewhat limited and susceptible to spammers' attempts at circumvention.